Pre-cast linings for hydropower tunnels: Advantages and successes

Pre-cast concrete segmental linings have been increasingly used for the design and construction of long hydropower tunnels around the world as their advantages and successes over the past nearly 50 years have continued to be recognized in the industry as the most cost effective and low risk approach for safe future hydraulic operations without undue maintenance. Key advantages of the use of pre-cast concrete segmental linings include improved hydraulics, durability against abrasion, simple pre-design and construction implementation without decision-making, high quality control of fabrication, rapid installation for overall high productivity and shorter construction durations, greater cost certainty, confident long-term stability for safe and uninterrupted future hydraulic operations for the full range of tunnel sizes generally varying from 3 m to 10 m and improved worker safety. The risks associated with the use of pre-cast tunnel linings are limited as the design and construction practice has become a well-established approach.